public void testRemoveMergedRegion() {
Workbook workbook = new XSSFWorkbook();
CTSheet ctSheet = CTSheet.Factory.newInstance();
CTWorksheet ctWorksheet = CTWorksheet.Factory.newInstance();
XSSFSheet sheet = new XSSFSheet(ctSheet, ctWorksheet, (XSSFWorkbook) workbook);
Region region_1 = new Region("A1:B2");
Region region_2 = new Region("C3:D4");
Region region_3 = new Region("E5:F6");
sheet.addMergedRegion(region_1);
sheet.addMergedRegion(region_2);
sheet.addMergedRegion(region_3);
assertEquals("C3:D4", ctWorksheet.getMergeCells().getMergeCellArray(1).getRef());
assertEquals(3, sheet.getNumMergedRegions());